local DCF-clock not connected to RxD - NTP

This is a discussion on local DCF-clock not connected to RxD - NTP ; Hello, is it possible to connect a DCF-clock to any other pin and use (x)ntpd? My problem is,that RxD can only be used with very low baudrates (50) and my serial port can only set to values 200 and above. ...

+ Reply to Thread
Results 1 to 8 of 8

Thread: local DCF-clock not connected to RxD

  1. local DCF-clock not connected to RxD

    Hello,

    is it possible to connect a DCF-clock to any other pin and use (x)ntpd?
    My problem is,that RxD can only be used with very low baudrates (50)
    and my serial port can only set to values 200 and above. So CTS, DSR,
    DCD or RI are a better choice. Is there a driver for (x)ntpd available?

    Best regards, Reinhold


  2. Re: local DCF-clock not connected to RxD

    Reinhold,

    Are you using a DCF receiver with raw timecode output (one impulse per
    second)
    or a receiver with nicely formatted ASCII output messages?

    For 'clocks' with raw timecode output, NTP sets the baud rate of the
    serial port to
    50. That's the way it works.

    For clocks with ASCII output, NTP typically sets the baud rate of the
    serial port to match
    the default speed of the clock's serial output.

    Can you tell us the brand and type of clock that you are using?

    Paul


  3. Re: local DCF-clock not connected to RxD

    Hello Paul,

    I'm using a modified Meinberg AW-02 receiver that outputs a raw
    timecode with TTL-level.
    NTP try to set a baud rate of 50 but my hardware does not support this

    Reinhold


  4. Re: local DCF-clock not connected to RxD

    Hallo Reinhold,

    At a baud rate of 50, one character (start bit, 8 data bits, stop bit)
    at the serial
    interface has a duration of 0.2 sec.

    The 'pips' that DCF77 transmits have a duration of either 0.1sec or
    0.2sec, and
    therefore appear as characters either with all bits set or with the
    first four data bits set.

    If you try to set to serial interface to a baud rate other than 50, you
    would have to do
    significant re-engineering of the bit decoding algorithms. You might
    want to look at
    parseutil/dcfd.c, lines 512ff, for more information about how it's
    done.

    Gre,
    Paul


  5. Re: local DCF-clock not connected to RxD

    Hello Reinhold,

    Reinhold wrote:
    > Hello Paul,
    >
    > I'm using a modified Meinberg AW-02 receiver that outputs a raw
    > timecode with TTL-level.
    > NTP try to set a baud rate of 50 but my hardware does not support this


    If I remember correctly we have already discussed this on the phone, and you
    are using a RS-232-to-USB converter.

    While this may work with a device which transmits an ASCII string (in spite
    of the jitter introduced by the USB bus) I doubt NTP's RAW_DCF driver would
    at all be able to decode the raw DCF77 time marks properly after they have
    been transferred via USB.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  6. Re: local DCF-clock not connected to RxD

    Hello Martin,

    > If I remember correctly we have already discussed this on the phone, and you
    > are using a RS-232-to-USB converter.


    yes, we do

    > While this may work with a device which transmits an ASCII string (in spite
    > of the jitter introduced by the USB bus) I doubt NTP's RAW_DCF driver would
    > at all be able to decode the raw DCF77 time marks properly after they have
    > been transferred via USB.


    I have to try this because we want to discuss all possibilities. The
    jitter is no problem for our needs, if NTP accept this source

    Reinhold


  7. Re: local DCF-clock not connected to RxD

    Just a suggestion as I don't have your device.
    If you can dispense with the rs-232-> usb , then why not try
    connecting to DCD and using the SHM driver in conjunction
    with Jonathan Buzzards DCF radioclock daemon.
    http://www.buzzard.me.uk/jonathan/radioclock.html
    There is no needfor any particular baud rate to be set
    as there is no host -> refclock comms. You would probably
    need to check the polarity of the signal as it uses assert
    to start the timing of interrupts and signal pulse length
    on the DCD pin.

    regards,
    Mike

    Reinhold wrote:
    > Hello Martin,
    >
    >
    >>If I remember correctly we have already discussed this on the phone, and you
    >>are using a RS-232-to-USB converter.

    >
    >
    > yes, we do
    >
    >
    >>While this may work with a device which transmits an ASCII string (in spite
    >>of the jitter introduced by the USB bus) I doubt NTP's RAW_DCF driver would
    >>at all be able to decode the raw DCF77 time marks properly after they have
    >>been transferred via USB.

    >
    >
    > I have to try this because we want to discuss all possibilities. The
    > jitter is no problem for our needs, if NTP accept this source
    >
    > Reinhold
    >


  8. Re: local DCF-clock not connected to RxD

    Hello Mike,

    > If you can dispense with the rs-232-> usb , then why not try
    > connecting to DCD and using the SHM driver in conjunction
    > with Jonathan Buzzards DCF radioclock daemon.
    > http://www.buzzard.me.uk/jonathan/radioclock.html


    thank you very much. Works great

    > There is no needfor any particular baud rate to be set
    > as there is no host -> refclock comms. You would probably
    > need to check the polarity of the signal as it uses assert
    > to start the timing of interrupts and signal pulse length
    > on the DCD pin.


    I've modified radioclock to invert DCD for a first test. Now our
    hardware group have to do this right...

    Thanks, Reinhold


+ Reply to Thread